A rocket, missile, or other launch vehicle may consist of a number of stages, each of which contains its own engines and propellant and which may be fired successively at different phases of flight. Once a stage has expended its propellant, the stage may be jettisoned from the launch vehicle, thus reducing the mass of the remaining rocket. Similarly, once the last stage of the launch vehicle has been expended, the attached payload, such as a satellite, spacecraft, kill-vehicle, or warhead, may be separated from the upper stage in order to complete its tasks.
The various stages and payload of the rocket or missile may be attached to one another by one or more release mechanisms, such as explosive bolts or other pyrotechnic fasteners. These pyrotechnic fasteners may contain an explosive charge activated by a “squib” that when initiated, breaks the fastener mechanism into multiple pieces, thus releasing the attached components. The squib may be initiated, or “fired,” by applying an electric current to a bridgewire, bridge resistor, or other pyrotechnic initiator in the squib. For example, in order to deploy the payload at the end of the boost phase of flight, the launch vehicle's guidance computer or other flight control system may energize the bridgewires of the squibs in the release mechanisms securing the payload to the upper stage.
It may not be desirable to fire all the release mechanisms attaching the payload to the upper stage at the same time. For example, firing all the release mechanisms simultaneously may produce too much shock to the payload. In addition, the power systems of the launch vehicle may not be able to generate enough power to simultaneously initiate all the squibs for the release mechanisms. For example, a kill-vehicle on an anti-missile rocket may be secured to an ejector platform of the upper stage of the rocket by four separation nuts. Each of the separation nuts may contain two squibs, a primary and a redundant, requiring 3.5 amps of current be applied for 25 milliseconds to guarantee firing, according to manufacturer's specifications. Ensuring that all four separation nuts fire simultaneously may require up to 28 amps of current be applied to the squibs for 25 milliseconds, which may be beyond the power capabilities of the rocket.
It is with respect to these and other considerations that the disclosure made herein is presented.